D&E Workshop

11th fiapac Conference Ljubljana, Slovenia

2 October 2014

Methods of Cervical Dilation

Matthew F. Reeves, MD 2 October 2014

Cervical Dilation •  Review methods

– Rigid – Osmotic – Pharmaceutical

•  Discuss evidence for use – Early 2nd trimester – Late 2nd trimester

Methods of Cervical Dilation •  Rigid Dilators

– Active mechanical dilation over several minutes

•  Osmotic Dilators – Gradual dilation, usually over 2-24 hours

•  Pharmaceutical Dilators – Medication to induce cervical dilation

Rigid Dilators •  Hegar Dilators

–  An older rigid dilator –  Blunt-ended –  1 mm increments

•  1/2 mm increments available

–  More cervical injury compared to tapered (Pratt) dilators

Rigid Dilators •  Pratt Dilators

–  Tapered-ends –  Increase in diameter

more gradually than Hegar (2/3 mm)

•  Denniston Dilators –  Plastic version of Pratt

dilators

Rigid Dilators

Force Required to Dilate: Hegar vs. Pratt

Hulka,  AJOG,  1974  

Osmotic Dilators •  Hygroscopic rods placed

within the cervix •  Absorb water

–  Removal of water from cervix –  Swelling of dilators creates

mechanical pressure

•  Often called “tents” –  tent (2): n. A small cylindrical plug

of lint or gauze used to keep open or probe a wound or an orifice.

–  [Middle English tente, from Old French, from tenter, to probe, from Latin tentare, to feel, try; see tentative.]

Laminaria tents •  Commonly known as “Kelp” •  L. japonicum

–  Now Saccharina japonicum –  Kombu in Japanese

•  Laminaria digitata –  Does not perform as well

•  Sterilized with ethylene oxide –  Not completely sterilized –  But no evidence of increased

rates of infection

Laminaria tents

•  Swells to several times its dried diameter over 12-24 hours –  Creates mechanical force to dilate cervix –  Draws water out of cervix –  Increases serum & cervical prostaglandin levels

Laminaria japonica –  Kombu in Japanese

FAO: Guide to the Seaweed Industry

Dilapan •  Hypan tents,

– made of polyacrylonitrile hydrogel

– Completely synthetic – Allows more uniformity

in production – 4 mm by 65 mm

Dilapan-S

Lamicel •  A compressed polyvinyl alcohol polymer sponge •  Impregnated with 450 mg of Magnesium sulfate •  Available in 2 sizes

–  5mm –  3mm

•  Dilation not due to mechanical force –  Expanded sponge in soft –  Sponge may draw water out of cervix –  Lamicel induces collagenolytic activity –  Dilation often attributed to Magnesium

Pharmaceutical Dilators •  Misoprostol

–  A synthetic prostaglandin E1 analog –  Cheap & stable at room temperature

•  Gemprost –  Also a PGE1 analog, but requires refrigeration

•  Other prostaglandin –  Not commonly used on the US

•  Mefipristone –  Progesterone antagonist

•  Nitric Oxide Donors –  Rarely used; no significant effect in studies

Misoprostol

•  Misoprostol: analog of prostaglandin E1 – More stable than PGE1 – Lower cost than most prostaglandin analogs

Misoprostol •  Multiple routes:

–  Oral –  Vaginal –  Buccal –  Sublingual –  Rectal

•  Oral or SL gives quicker higher peak

•  Vagina gives greater area under the curve –  And local effect –  400mcg vaginally compared

to 400 mcg orally: •  Double AUC at 4 hours •  Triple AUC at 6 hours

Zieman,  ObGyn,  1997  

Uterine Effects of Misoprostol

Danielsson,  Ob  &  Gyn,  1999  

200  mcg:  

400  mcg:  

Uterine  Tone   Montevideo  Units  

Changes in the Cervix after Misoprostol •  Misoprostol induces

inflammation in cervical stroma –  Similar to changes with labor

•  3 hours after misoprostol, cervical biopsies show increases in the following: –  CD45

•  leukocyte common antigen –  Matrix metalloproteinase 8

•  degrades fibrillar collagens –  Matrix metalloproteinase 9

•  degrades collagen IV of basement membranes

Aronsson,  Contracep@on,  2005  

CD45  

CD68  

MMP8   MMP9  

Mifepristone •  Mifepristone is a anti-progestin

(and anti-glucocorticoid) •  Studied at 4-36 hours before

D&E •  Expensive

–  May still be cost effective

Misoprostol in Singapore for 3-4 hours: Which Dose is Best? •  Double-blind RCT •  4 groups in 1st trimester

received vaginal misoprostol –  200 mcg (n=30) –  400 mcg (n=30) –  600 mcg (n=30) –  800 mcg (n=30)

•  Demographics –  Mean Age: 20-22 yo –  Mean GA: 8 weeks –  All nulliparous

•  Evaluated at 3-4 hours

Singh,  ObGyn,  1998  

Misoprostol in Singapore for 3-4 hours: Which Dose is Best?

•  400 mcg dose thought to be optimal •  Forces needed to dilate not measured

Singh,  ObGyn,  1998  

Misoprostol in Singapore #2: Does Dose Equal Time?

•  Double-blind RCT •  3 groups in 1st trimester

received vaginal misoprostol –  400 mcg for 3 hrs (n=60) –  600 mcg for 2 hrs (n=60) –  800 mcg for 2 hrs (n=60)

•  Demographics –  Mean Age: 20-21yo –  Mean GA: 7.5-8 weeks –  All nulliparous

Singh,  ObGyn,  1999  

Misoprostol in Singapore #2: Does Dose Equal Time?

•  400 mcg dose again thought to be optimal

Singh,  ObGyn,  1999  

Misoprostol in Hong Kong: Measuring Forces with a Placebo Arm •  Double-blind RCT •  5 groups at 8-12 wks

received misoprostol for 3 hours –  Placebo (n=44) –  200 mcg oral (n=43) –  400 mcg oral (n=40) –  200 mcg vaginal (n=40) –  400 mcg vaginal (n=37)

•  Demographics –  Mean Age: 21-23yo –  Mean GA: 9.5-10 weeks –  All nulliparous

•  Evaluated at 3 hours

Ngai,  Hum  Repro,  1999  

Misoprostol in Hong Kong: Measuring Forces with a Placebo Arm

Ngai,  Hum  Repro,  1999  

Misoprostol in Mozambique: Less Miso, More Time •  Double-blind RCT •  2 groups at 8-12 wks

received vaginal misoprostol for 6 hours –  Placebo (n=50) –  200 mcg (n=50)

•  Demographics –  Mean Age: 24-25yo –  Mean GA: 8.5 weeks –  Mean Parity: 1.4

•  Evaluated at 6 hours

Bugalho,  ObGyn,  1994  

First Trimester Dilation in San Francisco •  Double-blind RCT •  106 women at 7-14 weeks

–  mean 9 weeks •  3 treatment groups

–  1 medium Laminaria –  400 mcg oral Misoprostol –  400 mcg vaginal

Misoprostol •  Each for 4 hours •  Mean Dilation (French):

–  Lam: 26mm –  Oral Miso: 24mm –  Vag Miso: 28mm

MacIssac,  ObGyn,  1999  

First-Trimester Dilation in San Francisco

MacIssac,  ObGyn,  1999  

p=0.001   p=0.21  

  Bleeding  ≥  1  soaked  pad:  0  of  14  lam;  2  of  45  oral  miso;  3  of  47  vaginal  miso  

Cramping,  Nausea/Emesis,  

Fever  

Cervical  Dila@on  

A Conceptual Model of the Effects of Misoprostol

•  A low dose of misoprostol seems to give good cervical preparation

•  Avoids side-effects

•  But it needs time to work

Pregnancy Expulsion

Time

Dose

Misoprostol vs. Laminaria for 13-16 week D&E •  Double-blinded RCT with 83

women •  2 groups:

–  3-6 medium laminaria for 24 hours –  400 mcg vaginal misoprostol for 3-4

hours •  Much better dilation with laminaria

–  Mean dil: 43 vs. 33 fr. (p<0.001) –  MDs preferred laminaria group –  All used laminaria normally

•  Subjects strongly preferred a one-day procedure –  despite more pain/cramping

Goldberg,  Contracep@on,  2005  

Adding Buccal Misoprostol to Laminaria at 13-16 weeks

•  RCT with 72 women in Portland •  Laminaria overnight •  400 mcg Miso for 90 minutes

•  No difference in dilation or procedure time – This is not surprising: not enough time – Still a 24-hour procedure

Edelman,  Contra,  2005  

Laminaria or Lamicel for 4 hours •  Double-blind RCT •  2 groups at 14-16 wks

received for 3-4 hours: –  Laminaria (n=110) –  Lamicel (n=109)

•  Demographics –  Mean Age: 22yo –  Mean GA: 15 weeks –  Mean Parity: 0.6

•  Evaluated at 3.7 hours

•  Results: •  Initial Dilation ≥ 37 fr

–  Laminaria: 47% –  Lamicel: 48%

•  Able to dilate to 43 fr –  Laminaria: 95% –  Lamicel: 96%

Grimes,  ObGyn,  1987  

Lamicel vs. Dilapan for 20 hours: When time is not the issue •  Evaluator-blinded

quasi-RCT •  2 groups at 13-16 wks

received for 20 hours: –  1 Lamicel (n=23) –  1 Dilapan (n=28)

•  Demographics –  Mean Age: 24yo –  Mean GA: 15 weeks –  40% nulliparous

Wells,  AJOG,  1989  

Vasopression & Cervical Dilation: The Only Study •  Double-blinded RCT of

dilation at hysteroscopy •  52 non-pregnant women,

mean age 40 –  On Lupron for myoma

resection •  Intracervical injection of

–  20cc saline –  20cc saline with 1u

vasopressin •  Shorter time to dilate to

11mm (p<0.001) –  Vaso: 132 sec (169-359) –  Control: 695 sec

(302-1249)

Phillips,  ObGyn,  1997  

D&E: Cervical Preparation •  To open the cervix before the procedure •  Options

– Osmotic dilators: •  Laminaria: overnight •  Dilapan 3-24 hours

– Misoprostol •  400 mcg vaginal 3-6 hours before

– Mifepristone •  200 mg 24 hours before

– More time with more weeks

WHO.  Clinical  prac@ce  handbook  for  safe  abor@on.  Geneva;  2014.  

Procedure room

Timeline: Induction vs. D&E

D&E  

Wait  2-­‐4  hours  

Misoprostol    400  mcg  vaginally  

Wait  20-­‐24  hours  

Mifepristone  200  mg  

Perform  D&E  

Wait  4-­‐6  hours  

Ini@a@on  of  cervical  prepara@on  

Dilation in the 2nd Trimester

•  Dilapan is better than laminaria – Better for overnight – Faster for same-day

•  Misoprostol work •  Women are willing to trade temporary

discomfort to lessen total time

Thank you

mreeves@prochoice.org